1. Field of the Invention
The present invention relates to the technical field of an information generating apparatus, a recording medium where an information generating program is recorded, and an information generating method for generating, at the time of displaying a map image including a road, symbol data for displaying a symbol indicative of a start point or end point of a facility provided along a road, in a position where the start point or end point of the facility exists.
2. Related Background Art
Hitherto, a navigation system is known, navigating a vehicle by displaying, on a screen, a road map of a peripheral area including the present position of the vehicle, a route to the destination of the vehicle, and the like.
In such a navigation system, at the time of displaying a road map on the screen, generally, information such as map symbols, the name and related information of a feature, the name of a road, and the like is displayed together with images of the background and roads.
As such information, for example, the symbol of a facility provided along a road, such as tunnel, bridge, railroad crossing, or the like is also displayed. For example, Japanese Unexamined Patent Publication No. H8-292054 discloses an in-vehicle path searching apparatus displaying a flag indicative of an entrance or exit in the position of the entrance or exit of a tunnel existing on a path to a destination.
Such a symbol or character information is called a annotation or the like. Information is displayed as described above on the basis of annotation data specifying data of the annotation, display position, and the like.
Map data used for displaying a road map on a screen and navigating a vehicle include not only the annotation data but also various data such as node data specifying information of a branch point or the like, link data specifying the position, shape, connection, and the like of a road, and background data specifying the position, shape, and the like of a feature, and the amount of the data is enormous.
Consequently, map data are often maintained by a group (of people) which is assigned to each of the data. For example, the road link data, the node data, and the like are maintained by a road data creation group, and the annotation data, the background data, and the like are maintained by a map creation group.
Facilities above provided along roads such as tunnels, bridges, and railroad crossings are information which can be also referred to as attributes indicative of the features in one aspect of the roads. Facility data that define information of the facilities are often defined, for example, in link data itself or defined in correspondence with the link data. Consequently, in many cases, the facility data are maintained by the road data creation group. Therefore, after addition, change, erasure, or the like of the information of a facility is performed by the road data creation group, the map creation group has to match annotation data to the corrected data.
However, for example, to maintain the annotation data of a tunnel, a bridge, or the like, the map creation group manually refers to the facility data, recognizes the position of the entrance and exit of the tunnel or the like, and adjusts the position of the annotation to the position. Consequently, the cost required for maintaining the annotation data is excessively high.
In the case of displaying a road map on a plurality of scales, considering viewability of the road map and the like, in some cases, a specification of whether a annotation is displayed or not is preliminarily determined on each of the scales in accordance with the length, kind, and the like of a tunnel or the like. However, when annotation data are manually maintained, whether the annotation data are displayed or not is determined from a personal viewpoint of each of persons in charge, so that annotation data may not be generated to the specifications.
The present invention has been achieved from the above points and an object of the invention is to provide an information generating apparatus, a recording medium where an information generating program is recorded, and an information generating method for efficiently and properly generating symbol data such as annotation data for displaying a symbol such as a annotation in a position where the start point or end point of a facility such as a tunnel provided along a road exists.